The optimal treatment strategy for women who initiate antiretroviral therapy during pregnancy is not known. Although PI-based antiretroviral regimens are prescribed with increasing frequency among pregnant women, the efficacy and safety of this approach is unknown. Pregnant women are at increased risk for glucose intolerance and insulin resistance; PIs are associated with glucose intolerance. Physiologic differences between pregnant women and nonpregnant adults may alter the pharmacokinetics of antiretroviral regimens. Fetal safety considerations and effects on perinatal HIV transmission must also be considered when selecting an antiretroviral regimen for pregnant women. This trial will compare PI-based and PI-sparing antiretroviral regimens for women initiating antiretroviral therapy in pregnancy.